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1.
王煜  方志杰  汪建敏 《精细化工》2007,24(12):1212-1214,1235
对合成结构较简单的4种以芳基取代丙烯腈为骨架的芪类化合物的常用合成方法进行了研究。以取代苯甲醛和取代苯乙腈为原料,在氮气保护、甲醇钠作催化剂等条件下,通过一步缩合反应,高收率得到(Z)-2-(3,4-二甲氧苯基)-3-(4-甲氧苯基)丙烯腈(Ⅰ)、(Z)-2-(3,4-二甲氧苯基)-3-(3,4-二甲氧苯基)丙烯腈(Ⅱ)、(Z)-2-(3,4-二甲氧苯基)-3-(4-二甲氨基苯基)丙烯腈(Ⅲ)、(Z)-3-(3,5-二甲氧苯基)-2-(4-甲氧苯基)丙烯腈(Ⅳ),实测收率分别为98.3%、96.0%、83.4%及88.8%。  相似文献   

2.
以丙烯酸丁酯(BA)为软单体、丙烯酸甲酯(MA)为硬单体、2-乙基己烷丙烯酸酯(2-EHA)为特软单体、丙烯酸(AA)为亲水单体、二甲基丙烯酸乙二醇酯(EGDM)为交联剂、平平加(O-25)和十二烷基硫酸钠(SDS)为复合乳化剂、过硫酸钾(KPS)和偏重亚硫酸钠(SM)为氧化还原型引发剂,采用乳液共聚法合成环保型静电植绒胶。结果表明:当m(BA)∶m(MA)∶m(2-EHA)∶m(AA)∶m(EGDM)∶m(0-25/SDS)∶m(KPS/SM)=100∶40∶4∶8∶3∶(26/7)∶(1/1.0)时,胶粘剂稳定性较好;此时静电植绒织物中无游离甲醛含量和APEO含量,其摩擦牢度2 500次且柔软度为4~5级,符合生态服装面料的使用要求。  相似文献   

3.
以温度为函数的硝仿系炸药的爆发分解反应动力学参数   总被引:2,自引:0,他引:2  
用爆发点试验装置测定了6种硝仿系炸药:2,2,2-三硝基乙基-N-硝基-甲胺(TNMA)、二(2,2,2-三硝基乙基-N-硝基)乙二胺(BTNEDA)、4,4,4-三硝基丁酸-2,2,2-三硝基乙酯(TNETB)、二(2,2,2-三硝基乙醇)缩甲醛(BTNF)、1,1,1,3-四硝基丙烷(TETNP)和二(2,2,2-三硝基乙基)硝胺(BTNNA)在不同温度下的爆发延滞期.依据谢苗诺夫方程lnt_(lag,i)=E_α/RT_i-lnA_α,由lnt_(lag,i)对1/T_i的关系,用作图法和最小二乘法计算了爆发分解反应的表观活化能(E_α)、指前因子(A_α)和5 s爆发点.用非线性等转化率积分法所得的表观活化能(E_α)校验了由lnt_(lag,i)~1/_Ti关系得到的Eα值.借助热力学关系式,计算了爆发分解反应的活化热力学参数[活化自由能(ΔG≠),活化焓(ΔH≠)和活化熵(ΔS≠)].结果表明: (1) E_α和作图法所得E_α间的相对误差在±5%以内; (2) E_α与最小二乘法所得E_α相等的事实佐证了不同温度下爆发分解反应延滞期内的分解深度是相等的,所得E_α和A_α值是可接受的,谢苗诺夫方程推导过程中采用A_α>>G(α)的假设是合理的; (3) 以5 s爆发点和ΔG~#为判据,6种硝仿系炸药对热抵抗能力的次序为:TNETB>BTNF>BTNEDA>TETNP>TNMA>BTNNA.  相似文献   

4.
Membrane proteins are made soluble in aqueous buffers by the addition of various surfactants (detergents) to form so-called protein-detergent complexes (PDCs). Properties of membrane proteins are commonly assessed by unfolding the protein in the presence of surfactant in a buffer solution by adding urea. The stability of the protein under these conditions is then monitored by biophysical methods such as fluorescence or circular dichroism spectroscopy. Often overlooked in these experiments is the effect of urea on the phase behavior and micellar microstructure of the different surfactants used to form the PDCs. Here the effect of urea on five polyoxyethylene surfactants - n-octylytetraoxyethylene (C(8)E(4)), n-octylpentaoxyethylene (C(8)E(5)), n-decylhexaoxyethylene (C(10)E(6)), n-dodecylhexaoxyethylene (C(12)E(6)) and n-dodecyloctaoxylethylene (C(12)E(8)) - is explored. The presence of urea increases the critical micelle concentration (CMC) of all surfactants studied, indicating that the concentration of both the surfactant and urea should be considered in membrane protein folding studies. The cloud point temperature of all surfactants studied also increases with increasing urea concentration. Small-angle neutron scattering shows a urea-induced transition from an elongated to a globular shape for micelles of C(8)E(4) and C(12)E(6). In contrast, C(8)E(5) and C(12)E(8) form more globular micelles at room temperature and the micelles remain globular as the urea concentration is increased. The effects of increasing urea concentration on micelle structure are analogous to those of decreasing the temperature. The large changes in micelle structure observed here could also affect membrane protein unfolding studies by changing the structure of the PDC.  相似文献   

5.
The polymeric procyanidins extracted from Acacia confusa stem bark were fractionated with a step gradient of water, methanol and acetone on a Sephadex LH-20 column. The antioxidant activity of the collected fractions was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging and ferric reducing/antioxidant power (FRAP) assays. All fractions possessed potent antioxidant activity with the highest activity observed for fraction F9. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and reversed-phase high performance liquid chromatography (RP-HPLC) analyses suggested that the collected fractions consisted primarily of oligomeric and polymeric procyanidins, with different polymer ranges and most abundant polymer size. For each fraction, catechin and epicatechin were present as both terminal and extension units, and epicatechin was the major component in the extended chain. The mean degree of polymerization (mDP) of each fraction differed, ranging from 1.68 (fraction F2) to 17.31 (fraction F11). There was a relationship between antioxidant activity (IC50/DPPH and FRAP) and mDP (R(2) (DPPH) = 0.861, P = 0.006 and R(2) (FRAP) = 0.608, P = 0.038), respectively. However, the highest antioxidant activity of fraction (F9) was not coincident with the maximum mDP of fraction (F11).  相似文献   

6.
两种4-羟基吡啶(HP)的盐酸盐:HP.HCl(A)和(HP)2.HCl.H2O(B)具有不同的晶体结构,但在水溶液中它们应该是同样的HP共轭酸碱体系。为了得到HP合成工艺中需要的等电点(I)和离解常数Ka1两项参数和有必要证明在水溶液中(A)和(B)是同样的共轭酸碱体系,用pH计测定的酸碱滴定法,测定了HP的等电点(I)和离解常数Ka1,证明(A)和(B)是同样的共轭酸碱体系,并对上述参数进行了不确定度评定。  相似文献   

7.
The antifertility activity of organoantimony(III) complexes PhSb[RC(NC(6)H(4)S)CH(2)(NC(6)H(4)S)CR'] {R' = CH(3) (R(1)) and R = R' = CF(3) (R(2))} derived from corresponding sterically hinlered bifuinctional tetradentate ligands in the male rats was determined. The administration of compounds R(1) and R(2) at the dose level of 20 mg/kg. b. wt. siignificantly reduced the weights of testes and epididymides. Auxiliary glands showed a significant reduction after the treatment of compound R(1) only. Treated animals showed a notable depression of spermatogenesis. The preleptotene spermatocytes were decreased by 76.19 and 47.06; the secondary spermatocytes by 87.4% and 54.87337; and the step-19 spermatids by 72.9 and 46.77% respectively, following the compound R(1) and R(2) treatment. Reduced sperm count and motility resulted in 100% negative fertility in both the treated groups. A significant fall in the content of various biochemical parameters of eproductive tissues was observed after R(1) and R(2) treatment in comparison to controls.  相似文献   

8.
The oxidation of naphthalene (1) (Scheme 1) in dichloromethane or acetonitrile with excess ozone gives phthalic aldehyde (3), 2-formyl benzoic acid (4) and phthalic anhydride (8). Small amounts of the (E)- and (Z)-isomer of 3-phenyl-(2-formyl)-propenal (10) and (11) are also observed in some cases. The reaction is faster in acetonitrile than in dichloromethane owing to the higher solubility of ozone in the former solvent. The reaction is faster on lowering the temperature because of the increase of the concentration of ozone in solution at lower temperature. With a 1:1 or a 1:2 naphthalene:ozone ratio high conversion and low selectivity for the anhydride (8) is observed.  相似文献   

9.
The fate of major and minor components of soybean oil is examined at each stage of processing. Relationships are then drawn upon the effect on the quality of finished oil. General topics covered are (a) triglycerides and polyunsaturated fatty acids, (b) free fatty acids, (c) mono- and diglycerides, (d) phospholipids, (e) minor constituents, such as tocopherols, color bodies, and metal ions, (f) rearrangement and decomposition products, (g) foreign or toxic compounds not native to soya and (h) other additives, such as refining aids.  相似文献   

10.
Cobalt, being essential metal, influences different physiological and enzymatic functions. As cobalt does not accumulate in the body, Co-compounds have relatively low toxicity. The aim of the present study is the effect of complexes of Co(II) with aminoacids - lysine, arginine, histidine and serine on HSV-1 replication. No effect of [O(2)Co(his)(4)].nH(2)O and [O(2)Co(arg)(2)].nH(2)O on HSV-1 infection in vitro was found. Both, [O(2)Co(lys)(2)].nH(2)O and [O(2)Co(ser)(2)].nH(2)O suppress the attachement of HSV-1 particles onto target cells and the viral replication as well. Moreover, the properties of the particular Co-complex (charge, stability, structure) are manifestated by their virucidal effect. Thus, [O(2)Co(ser)(2)].nH(2)O irreversibly inhibits the infectious activity of free HSV-1 virions, while virucidal effect of [O(2)Co(lys)(2)].nH(2)O is completely reversible after the 2h of contact.  相似文献   

11.
以1-(2-甲基丙基)-4-氯-1H-咪唑并[4,5-c]喹啉(Ⅰ)为原料与哌啶反应合成了1-(2-甲基丙基)-4-[哌啶-1-基]-1H-咪唑并[4,5-c]喹啉(Ⅱ),当用甲苯为溶剂,n(Ⅰ)∶n(哌啶)∶n(K2CO3)=1∶2∶0.3时,Ⅱ的收率为88.5%;Ⅰ与三倍过量的吗啉反应合成1-(2-甲基丙基)-4-[吗啉-4-基]-1H-咪唑并[4,5-c]喹啉(Ⅲ),收率86.5%;Ⅰ与三倍过量的哌嗪在体积分数50%的1,4-二氧六环水溶液中反应合成1-(2-甲基丙基)-4-[哌嗪-1-基]-1H-咪唑并[4,5-c]喹啉(Ⅳ),收率59%。Ⅱ、Ⅲ、Ⅳ的合成工艺均较简单。  相似文献   

12.
The specific rates of solvolysis of isobutyl fluoroformate (1) have been measured at 40.0 °C in 22 pure and binary solvents. These results correlated well with the extended Grunwald-Winstein (G-W) equation, which incorporated the N(T) solvent nucleophilicity scale and the Y(Cl) solvent ionizing power scale. The sensitivities (l and m-values) to changes in solvent nucleophilicity and solvent ionizing power, and the k(F)/k(Cl) values are very similar to those observed previously for solvolyses of n-octyl fluoroformate, consistent with the additional step of an addition-elimination pathway being rate-determining. The solvent deuterium isotope effect value (k(MeOH)/k(MeOD)) for methanolysis of 1 was determined, and for solvolyses in ethanol, methanol, 80% ethanol, and 70% TFE, the values of the enthalpy and the entropy of activation for the solvolysis of 1 were also determined. The results are compared with those reported earlier for isobutyl chloroformate (2) and other alkyl haloformate esters and mechanistic conclusions are drawn.  相似文献   

13.
Malignant pleural mesothelioma (MPM) cells are characterized by chemoresistance associated with glutathione (GSH) metabolism. Ethacrynic acid (EA) is able to inhibit the detoxifying enzyme glutathione-S-transferase (GST), which catalyzes the conjugation between GSH and Pt-based drugs. With the aim of obtaining active bifunctional drugs, a Pt(II) complex containing two EA moieties as leaving groups, namely cis-diamminobis(ethacrynato)platinum(II), was synthesized, characterized, and tested on four MPM cell lines. The resulting antiproliferative activity was compared with that elicited by the analogue Pt(IV) complex, cis,cis,trans-diamminodichloridobis(ethacrynato)platinum(IV) (ethacraplatin) and by the co-administration of free EA and cisplatin. The Pt(II) and Pt(IV) bifunctional complexes showed poorer performance than the reference drug cisplatin alone or in combination with EA. After treatment, cellular GST activity remained consistently unchanged, while the GSH level increased.  相似文献   

14.
以聚环氧乙烷-聚环氧丙烷-聚环氧乙烷三嵌段共聚物(P123)为模板剂、正硅酸甲酯(TMOS)为硅源,采用水热法合成出孔径大于100 nm的硅基囊泡材料。同时采用两步法合成出带有硅烷偶联基团的有机自由基引发剂2-溴-2-甲基丙酸丁酯基三乙氧基硅烷(BPE)和2-溴-2甲基丙酸丁酯基二甲基氯硅烷(BPCM)。再利用偶联基团与囊泡材料孔道内表面的硅羟基偶联反应将自由基引发剂BPE和BPCM分别接枝到囊泡内表面,元素分析发现BPCM具有更高的接枝效率。然后在囊泡孔道内分别引发烯烃单体甲基丙烯酸甲酯(MMA)和甲基丙烯酸丁酯(BMA)的原子转移自由基聚合(ATRP)反应,使单体在表面自由基上逐一反应形成聚合物刷。透射电镜(TEM)表征结果表明,孔道内表面接枝上了聚合物后囊泡保持较为完好。通过化学方法将聚合物切割下来,凝胶渗透色谱(GPC)分析发现接枝的PMMA和PBMA的数均分子量(Mn)分别为7600和11400,分子量分布指数(PDI)均为1.25。  相似文献   

15.
皮肤美白剂活性的化学评价研究   总被引:2,自引:0,他引:2  
刘宇红  李才广  彭金乱 《精细化工》2000,17(6):318-320,368
采用化学评价法 ,即通过测定皮肤美白剂对酪氨酸酶的活性抑制率 ,对目前常用的 6种皮肤美白剂的活性进行了评价 ,并与氢醌进行比较 ,得出 :( 1)各美白剂对酪氨酸酶活性的最高抑制率 ( 3 5h下 ) ,按由大到小次序排列如下 :氢醌 ( 98 3% ) >Biowhite( 90 5 % ) >Vc( 88 2 % )≥熊果苷 ( 87 8% )≥曲酸 ( 86 2 % ) >Vc磷酸酯钠 (自制 ,72 9% )≥Vc磷酸酯钠 (进口 ,72 7% ) >Vc磷酸酯镁 ( 41 1% )。探讨了美白剂活性评价与酪氨酸酶抑制率高低的关系。 ( 2 )得出各美白剂的ICmax( 3 5h下 )。 ( 3)得出美白剂作用时间与其酪氨酸酶抑制率关系曲线 ,该曲线表明 ,美白剂对酪氨酸酶的抑制率随其作用时间的增加而增加 ,时间过短将影响美白效果。采用自制酪氨酸酶体系进行评价 ,是一个行之有效的经济实用的方法  相似文献   

16.
Zhichao Liang 《Polymer》2011,52(12):2667-2676
The crystallization behavior has been investigated for poly(hexamethylene sebacate-co-hexamethylene suberate)s [P(HSe-co-HSu)] and poly(hexamethylene suberate-co-hexamethylene adipate)s [P(HSu-co-HA)] copolyesters by differential scanning calorimeter (DSC), wide angle X-ray diffraction (WAXD) and Fourier transform infrared (FTIR) spectrometer. Cocrystallization of comonomer units was found in the crystalline phase of both P(HSe-co-HSu) and P(HSu-co-HA) copolymers. Moreover, both P(HSe-co-HSu) and P(HSu-co-HA) copolymers exhibit isodimorphism. The PHSe and the PHSu type crystals were respectively developed in P(HSe-co-HSu)s, while the PHSu and the PHA type crystals were developed in P(HSu-co-HA)s respectively. The inclusion of the comonomer units in the PHSu type crystalline lattice is more favored than that in the PHSe type crystal of the P(HSe-co-HSu)s. Meanwhile, it is easier for the comonomer units to be incorporated into the PHA type crystalline lattice than into the PHSu type crystal of P(HSu-co-HA)s. Moreover, comparison between the isomorphic crystallization of P(HSe-co-HSu), P(HSe-co-HA) and P(HSu-co-HA) series copolyesters indicates that minimization of the difference in chemical structure helps in increasing the extent of cocrystallization of comonomer units.  相似文献   

17.
以钛酸四丁酯以及固态和液态的氧化石墨烯(GO)为前驱物,分别制备了标记为TiO_2-RGO(s)和TiO_2-RGO(l)的复合光催化剂。对制备的2种复合光催化剂进行了表征,并以亚甲基蓝(MB)为目标物,对比研究了2种催化剂的光催化效能。结果表明,TiO_2-RGO(l)和TiO_2-RGO(s)的能级带宽分别降低至2.8、2.9 e V;二者光降解MB的效能均优于TiO_2自身,且降解效率随着GO含量的增加而增加;当TiO_2与GO的质量比为1∶0.06时,TiO_2-RGO(l)和TiO_2-RGO(s)对MB的降解率分别为96%和84%。动力学研究表明:TiO_2-RGO(l)和TiO_2-RGO(s)的准一级反应速率常数分别是TiO_2的3.2倍和2.2倍。  相似文献   

18.
A number of catalysts of Pd(II), Pt (II), Rh (I) and Ir(I) induce rearrangements of O-allylic-S-methyl dithiocarbonates at 25° C. For most substrates, the Pd(II) and Pt(II) catalysts cause [3,3] sigmatropic (Claisen) rearrangements but the Rh(I) and Ir(I) catalysts give, in addition, other products depending on the catalyst and the substrate. The Claisen rearrangements observed with the Pd(II) and Pt(II) catalysts are believed to occur by a cyclization induced mechanism, whereas those rearrangements associated with the Rh(I) and Ir(I) catalysts, as well as in one case with the Pd(II) catalyst, appear to involve metal stabilized carbocation intermediates. When cyclic substrates are used retention of configuration is observed predominantly for all catalysts tried.  相似文献   

19.
Metal complexes of malonie acid (metal = Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I)) were prepared and only the Ag(I) complex inhibited the growth of Candida albicans. Malonate complexes incorporating the chelating 1,10-phenanthroline (1,10-phen) ligand showed a range of activities: good (Mn(II), Cu(II), Ag(I)); moderate (Zn(II)); poor (Co(II), Ni(II)). Metal-free 1,10-phen and Ag(CH(3)CO(2)) were also highly active. The metal-free non-chelating ligands 1,7- phenanthroline and 4,7-phenanthroline were inactive and the Cu(II), Mn(II) and Zn(II) complexs of 1,7-phen displayed only marginal activity. Whereas the Cu(II) malonate/1,10-phen complex induces significant cellular oxidative stress the Zn(II) analogue does not.  相似文献   

20.
The oxidation of carboxy-terminated polybutadiene (CTPB) and polypropylene (PP) has been investigated at temperatures above 150°C. Studies have also been made of the effects on the oxidation of these polymers of a number of transition metal chelates, namely, the bis(3,5-diisopropyl salicylato) (DIPS) derivatives of Co(II), Ni(II) and Cu(II), bis(3,5-diisopropyl salicylato) hydroxyaquo Cr(III), the bis(N-n-butyl salicylaldimino) (NBS) compounds of Cu(II) and Ni(II), and bis(stilbene dithiolato)nickel (II) (NiSDT). At the temperatures concerned, the antioxidant activity of some of the chelates, in particular the DIPS compounds, was limited by their thermal stability. NiSDT was found to be a uniquely effective antioxidant at temperatures up to ~290°C. Mechanisms have been proposed to account for the dual role, as both catalysts and inhibitors of thermal oxidation, of the DIPS and NBS chelates.  相似文献   

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